[from slang `big wheel' for a powerful person] A
person who has an active wheel bit. "We need to find a wheel
to unwedge the hung tape drives." (See wedged, sense 1.)
The traditional name of security group zero in BSD (to which
the major system-internal users like root belong) is
`wheel'. Some vendors have expanded on this usage, modifying
Unix so that only members of group `wheel' can go root.